Ink jet printing systems are known in which a print head defines one or more rows of orifices which receive an electrically conductive recording fluid, such as for instance a water based ink, from a pressurized fluid supply manifold and eject the fluid in rows of parallel streams. Printers using such print heads accomplish graphic reproduction by selectively charging and deflecting the drops in each of the streams and depositing at least some of the drops on a print receiving medium, while others of the drops strike a drop catcher device.
In the art of image processing it is known that the use of lookup tables (LUT's) provide the flexibility to manipulate incoming device-independent data and to transform it into device-specific output data. This process is used to correct the color from input devices, such as scanners, for use as output files suitable for printers. One example of such a transformation is the conversion of files from RGB (red, green, blue) into files of CMYK (cyan, magenta, yellow, and black).
Of particular interest in high speed ink jet printing system applications are the use of a set of one dimensional LUT's. Each one dimensional LUT independently transforms a specific color plane of a color image file into a new color plane of data that is tone corrected and ink limited. Such a technique is disclosed an claimed in commonly assigned, co-pending application Ser. No. 08/550,958, totally incorporated herein by reference. These tone correction transformations assure that there is a gradual and linearly increasing change in tone over the dynamic range of the printing system. These tables also transform the input data so as to limit the total amount of ink applied to the substrate. This feature, also disclosed in commonly assigned co-pending application Ser. No. 08/550,958, assures ink and substrate compatibility.
Unfortunately, some existing transformations render the printer imaging data with undesirable artifacts. At other times, the transformed data loses some necessary feature of the original image data. It is not the one dimensional LUT's themselves that cause these artifacts. Rather, it is the processes occurring after these transformations that further reduce the image data from continuous tone into binary files that can be imaged by the digital printing device.
It would be desirable to be able to know in advance the relationship between the transformed continuous tone image data and the resulting binary representation, on a level by level basis. This would allow for restriction, modification, or other alteration of the continuous tone data prior to reduction to the binary level. This is done for the purpose of optimizing the binary image file by eliminating unwanted artifacts and forcing desired dot structures in areas of the image where such modifications are deemed advantageous.